• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Replacing my Leafsprings, I would like to upgrade the rear end. I need help with that

Plymouth71

Waterslide Decal Artist
Local time
6:04 AM
Joined
Sep 13, 2013
Messages
346
Reaction score
146
Location
Great White North
I ordered some Leaf Springs from Summit last year, and I would like to install them this year. My car has highway gears, 2.76 I believe (I don't have access to the fender tag right now). I would like to have a sure grip axle. I have a 1971 Plymouth Satellite. I am beefing up the engine & transmission and don't want any drive-line failures. I'm wanting a little more oomph but I still want to be able to drive on the highway occasionally. I know a Dana 60 is highly sought after, but I'm not sure I'd find what I need as my area is a restoration hotbed and local parts for vintage cars are more difficult to dig up.

Seeing as I am new to doing this kind of modification, what things should I look for?
  • Wrecked pick ups? are there specific years/ etc that will bolt on?
  • What about the brakes? I have 11 inch drums and 14 inch road wheels?
  • What about the original rear end, can I make it a limited slip differential with a kit?
  • How do I determine the length from side to side? where should I be measuring.
Like most people I am trying to keep costs low, so I'm not looking for a custom made piece, rather something I can swap in.

Thank you so much for your time, I appreciate your assistance.
 
You don't need a Dana.
Get a set of 3:23 or 3:55 gears and a sure grip carrier.
A call to doctor diff would be a wise move.
 
If you have a 8 3/4, moderate power, and tires that don't "dead-hook".....you should be okay. If you have an 8 1/4 and big power....I'd be shopping for a rear axle.
 
I ordered some Leaf Springs from Summit last year, and I would like to install them this year. My car has highway gears, 2.76 I believe (I don't have access to the fender tag right now). I would like to have a sure grip axle. I have a 1971 Plymouth Satellite. I am beefing up the engine & transmission and don't want any drive-line failures. I'm wanting a little more oomph but I still want to be able to drive on the highway occasionally. I know a Dana 60 is highly sought after, but I'm not sure I'd find what I need as my area is a restoration hotbed and local parts for vintage cars are more difficult to dig up.

Seeing as I am new to doing this kind of modification, what things should I look for?
  • Wrecked pick ups? are there specific years/ etc that will bolt on?
  • What about the brakes? I have 11 inch drums and 14 inch road wheels?
  • What about the original rear end, can I make it a limited slip differential with a kit?
  • How do I determine the length from side to side? where should I be measuring.
Like most people I am trying to keep costs low, so I'm not looking for a custom made piece, rather something I can swap in.

Thank you so much for your time, I appreciate your assistance.

What will you use the car for? If street driving/cruising, Dana is way overkill. Look at the rear axle & figure out what it is. post a picture, crawl under it & get the casting numbers (on an 8 3/4 they're on the pinion housing behind the driveshaft. For performance use you want a limited slip (posi to the GM guys). You might find a used 8 3/4 pumpkin, otherwise a quality vendor is the way to go if you don't have the experience & tools. Good luck.
 
If you don't HAVE to have disc brakes, these are an alternative. I will never replace my 11" Hemi drums. These work good, stop straight, good modulation.

www.musclecarbrakes.com.
 
I agree with Dennis, drums work just fine if freshened up (good hoses, wheel cylinders, master cylinder & use good linings with freshly turned drums). I used 10" drums on my '65 drag car for many years, (no panic stops though). 11" are good.
 
to start with know what you have
Mopar_rear_id.jpg
 
The best low-buck upgrade I know is to locate an 8.75 rear from an E body, cut off the spring pads and weld new ones on .75" out from where the originals were, and install it. I don't know what the market is like up there, but here in FL we're tripping over E body rears, so they sell for pretty cheap.

Once you have that rear in, you can start shopping for what sort of center section you want, and once you find it you can swap it in in an hour or so.
 
The easiest and least expensive if you are not running a big block, would be to change the gears to a 3:23 or 3:55, 4 speed would be better with a 3:55 but the 8.25 axel will take any size gear up to about 4:10. I changed my 2.71 to 3.23 30 years ago. I have a 904 trans and 318, A big difference in acceleration and much more fun to drive, I know some one who changed from 3:23 to 3:90 with a 440 and a three speed trans. you may need a power steering cooler since the factory had this set on some models.
 
Finally got the car put of storage. Not sure which it is. Too round for the 7.25 I think.

20170427_190534.jpg
 
Yep, you have an 8.25, which is fine unless you're making some HP monster engine. If you're just doing some basic performance upgrades, the 8.25 will handle that fine.

You can add a limited-slip capability to it, but I've never done one.
 
Auto Transport Service
Back
Top